Tests: added Python test with threading.

test/python/threading/wsgi.py

@@ -0,0 +1,33 @@
+import sys
+import time
+import threading
+
+
+class Foo(threading.Thread):
+    num = 10
+
+    def __init__(self, x):
+        self.__x = x
+        threading.Thread.__init__(self)
+
+    def log_index(self, index):
+        sys.stderr.write(
+            "(" + str(index) + ") Thread: " + str(self.__x) + "\n"
+        )
+        sys.stderr.flush()
+
+    def run(self):
+        i = 0
+        for _ in range(3):
+            self.log_index(i)
+            i += 1
+            time.sleep(1)
+            self.log_index(i)
+            i += 1
+
+
+def application(environ, start_response):
+    Foo(Foo.num).start()
+    Foo.num += 10
+    start_response('200 OK', [('Content-Length', '0')])
+    return []

test/test_python_application.py

@@ -507,6 +507,19 @@ Connection: close
 
         self.assertEqual(self.get()['body'], '0123456789', 'write')
 
+    def test_python_application_threading(self):
+        """wait_for_record() timeouts after 5s while every thread works at
+        least 3s.  So without releasing GIL test should fail.
+        """
+
+        self.load('threading')
+
+        for _ in range(10):
+            self.get(no_recv=True)
+
+        self.assertIsNotNone(
+            self.wait_for_record(r'\(5\) Thread: 100'), 'last thread finished'
+        )
 
 if __name__ == '__main__':
     TestPythonApplication.main()